The prior art discloses a number of solutions by means of which a rotor of a centrifuge can be mounted firmly on a drive shaft. For example, it is known to press the rotor onto a conical seat of a drive shaft by means of a screw thread.
Self-locking attachments are also known, for example, from EP 0 911 080 A1. However, the described system is only suitable for specific rotor types that do not generate any forces (for example, buoyancy forces) contrary to the coupling direction.
DE 10 2008 045 556 A1 develops the principle of EP 0 911 080 A1 explicitly provides for counteracting buoyancy forces up to a force of approximately 100 N. At forces below this value, unlocking in the axial direction is impossible. However, this system reaches its limits when higher buoyancy forces and/or very high rotational speeds occur. In the case of high buoyancy forces and simultaneous twisting of the coupling elements, or in the case of diminished friction pairing properties, the self-locking feature of the system is overridden and unlocking in the axial direction can occur. Furthermore, the rotor gets jammed as a result of the high centrifugal forces at very high rotational speeds and the coupling cannot always be easily detached.
DE 10 2012 011 531 A1 discloses a versatile system suitable for mounting a great variety of different rotors on a drive head in a self-locking manner. The drive head has various types of coupling elements, which swivel into associated recesses in the rotor either separately or in combination with each other depending on the respective rotor to be connected. The self-locking is achieved by appropriate arrangement of sloped ramp faces on the coupling elements and the rotor. In terms of manufacturing, this is relatively expensive.
It is thus an object of the present invention to overcome the disadvantages of the prior art described above. More particularly, it is an object of the present invention to provide a drive head comprising a self-locking and quickly detachable coupling as well as a kit for a centrifuge and a centrifuge comprising said drive head, which can be manufactured at a lower cost without any loss in terms of reliability and ease of operation.